What type of interaction is primarily responsible for the aggregation of nonpolar molecules in water?

Which amino acid has a side chain that, due to its small size and lack of chirality, introduces conformational flexibility in protein loops?

Which amino acid’s side chain can form a zwitterionic resonance-stabilized interaction in the active site of some enzymes?

The following is an excerpt from a recent scientific publication:“Specific noncovalent interactions that are indicative of attractive, directional intermolecular forces have always been of key interest to medicinal chemists in their search for the ‘glue’ that holds drugs and their targets together. … we survey … three kinds of strong, specific, direct, enthalpy‑driven intermolecular forces, including hydrogen bond, halogen bond and salt bridge, involved in the formation of protein‑ligand complex architecture … biological functions … in conferring affinity and specificity for ligand recognition by host protein.” Which interactions are highlighted here as enthalpy‑driven contributors to affinity and specificity in drug design?

Which situation below would most weaken a hydrogen bond between two molecules?

The following is an excerpt from a recent scientific publication:”…illustrating an internal H‑bond sampled between the piperidine and secondary amine nitrogen atoms… Internal H‑bond observed for the isolated compound becomes less likely in the presence of waters.” What inference can be made about oliceridine’s intramolecular hydrogen bonding in physiological (aqueous) environment?

What is the dominant type of noncovalent interaction between the side chains of phenylalanine and tryptophan in a folded protein?

Which amino acid has a bulky, hydrophobic, aromatic side chain that plays a major role in protein-protein stacking interactions?

In a globular protein, which of the following amino acids is most likely found on the exterior surface interacting with water?

Which amino acid side chain is most likely to participate in metal ion coordination in metalloproteins due to its lone pair donor properties?